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Go Data Types

We use data types in Golang to determine the type of data associated with variables. For example,

var age int

Here, int is a data type that specifies that the age variable can store integer data.

The basic data types in Golang are

Data TypeDescriptionExamples
intInteger numbers.7123, 0, -5, 7023
floatNumbers with decimal points.20.2, 500.123456, -34.23
complexComplex numbers.2+4i, -9.5+18.3i
stringSequence of characters."Hello World!", "1 is less than 2"
boolEither true or false.true, false
byteA byte (8 bits) of non-negative integers.2, 115, 97
runeUsed for characters. Internally used as 32-bit integers.'a', '7', '<'

Now, let's discuss the commonly used data types in detail.

1. Integer Data Type

Integers are whole numbers that can have both zero, positive and negative values but no decimal values. For example, 0, 5, -1340.

We commonly use the int keyword to declare integer numbers.

var id int

Here, id is a variable of type integer.

You can declare multiple variables at once in the same line.

var id, age int

In Go programming, there are two types of integers:

  • signed integer int - can hold both positive and negative integers

  • unsigned integer uint - can only hold positive integers

There are different variations of integers in Go programming.

Data TypesSize
int/uinteither 32 bits (4 bytes) or 64 bits (8 bytes)
int8/uint88 bits (1 byte)
int16/uint1616 bits (2 bytes)
int32/uint3232 bits (4 bytes)
int64/uint6464 bits ( 8 bytes)
NOTE

Unless we have a specific requirement, we usually use the int keyword to create integers.

Example: Understanding Integer Type

package main
import "fmt"

func main() {
  var integer1 int
  var integer2 int

  integer1 = 5
  integer2 = 10

  fmt.Println(integer1)
  fmt.Print(integer2)
}

Output

5
10

If you want to learn more about creating variables, visit Go Variables.

2. Float Data Type

The float type is used to hold values with decimal points. For example, 6.7, -34.2

Keywords used: float32, float64

Here's an example,

var salary float64

There are two sizes of floating-point data in Go programming.

Data TypesSize
float3232 bits (4 bytes)
float6464 bits (8 bytes)
NOTE

If we define float variables without specifying size explicitly, the size of the variable will be 64 bits. For example,

// the size of the variable is 64
salary := 5676.3

Example: Understanding Float Type

// Program to illustrate float32 and float64 with example

package main
import "fmt"

func main() {
  var salary1 float32
  var salary2 float64

  salary1 = 50000.503882901

  // can store decimals with greater precision
  salary2 = 50000.503882901

  fmt.Println(salary1)
  fmt.Println(salary2)

}

Output

50000.504
50000.503882901

3. String Data Type

A string is a sequence of characters. For example, "Hello", "Hey there"

Keyword: string

Here's an example,

var message string

In Go, we use either double quotes or backticks to create strings.

var message string = "Hello World "
var message string =  `Hello World`

Example: Understanding String Type

// Program to create string variables

package main
import "fmt"

func main() {
  var message string
  message = "Welcome to Programiz"

  fmt.Println(message)

}

Output

Welcome to Programiz

4. Boolean Data Type

The boolean data type has one of two possible values either true or false.

Keyword: bool

var isValid bool

Example: Understanding bool Type

// Program to create boolean variables

package main
import "fmt"

func main() {
  var boolValue bool
  boolValue = false

  fmt.Println(boolValue)
}

Output

false

We will learn about booleans in detail in the Go Comparison and Logical Operators tutorial.

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